Autoquery Distinct on Joined Column

Having a couple convention based tables that are joined, I can’t determine how to return a query with the joined table’s distinct value. The ?Fields=Distinct Table2Column didn’t seem to work so I created a custom implementation where the req.DistinctField is the Field name (Table2Column or even Table2.Column) and that wasn’t working either. Can you recommend the best way to handle this scenario?

        var q = AutoQuery.CreateQuery(req, Request.GetRequestParams());
        q = q.SelectDistinct(req.DistinctField);
        return AutoQuery.Execute(req, q);

Here’s some valid Examples for SelectDistinct():

.SelectDistinct(x => x.Field) // single field
.SelectDistinct(x => new { x.Field1, x.Field2 }) // multiple fields
.SelectDistinct<T1,T2>((x,y) => new { x.Field1, y.Field2 }) //multi fields/tables